<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <!-- 
        自定义属性data-name=value
     -->
    <input type="button" value="hello" id="test">
    <script>
        var value = "change"
        var test = document.getElementById("test");
        test.onclick = function(){
           setTimeout(()=>{
               console.log(this.value);
           },300)   
        }
       
    </script>
</body>
</html>